Method for producing a conductor bar of transposed stranded conductors

Abstract

A method for producing a conductor bar including transposed stranded conductors for a large, rotating electric machine. The method includes a first step of cabling a plurality of electrically insulated individual wires to form a plurality of identical stranded conductors having an essentially circular cross section. In a second step the stranded conductors are helically wound around a winding spindle in the manner of a Roebel transposition so as to form a conductor loop, wherein the winding has a profile adapted to a final cross sectional shape of the conductor bar. In a third step, the winding spindle removed from the conductor loop. In a fourth step, the conductor loop undergoes a press-forming procedure that gives it the final cross sectional shape, especially, for example, a rectangular shape.

1. A method for producing a conductor bar of transposed stranded conductors for a large, rotating electric machine, the method comprising:
 in a first step, cabling a plurality of electrically insulated individual wires so as to form a plurality of identical stranded conductors each having an essentially circular cross section; 
 in a second step, helically winding the stranded conductors around a winding spindle according to a Roebel transposition so as to form a conductor loop, the winding spindle having a profile adapted to a final cross sectional shape of the conductor bar; 
 in a third step, removing the winding spindle from the conductor loop; and 
 in a fourth step, performing a press-forming procedure on the conductor loop so as to give the conductor loop the final cross sectional shape, wherein the final cross sectional shape is constant along a length of the conductor bar. 
 
   
   
     2. The method as recited in  claim 1 , wherein the final cross-sectional shape is rectangular. 
   
   
     3. The method as recited in  claim 1 , wherein the removing of the winding spindle leaves an empty space in the conductor loop and wherein the method further comprises inserting a strip-like intermediate insulating layer into the hollow space before the fourth step, the intermediate insulating layer being thinner than the winding spindle. 
   
   
     4. The method as recited in  claim 3 , wherein the intermediate insulating layer includes a thin strip of a heat-resistant, voltage-proof, mechanically deformable insulating material. 
   
   
     5. The method as recited in  claim 3 , wherein the removing of the winding spindle is performed in a lengthwise direction and wherein the inserting of the intermediate insulating layer is performed at the same time as the removing of the winding spindle. 
   
   
     6. The method as recited in  claim 2 , the profile of the winding spindle has a rectangular cross section and rounded-off edges. 
   
   
     7. The method as recited in  claim 1 , wherein the fourth step includes gluing together the individual wires during the press-forming procedure. 
   
   
     8. The method as recited in  claim 7 , wherein the gluing is performed by heating up the conductor loop in a press-forming device before and/or during the press-forming procedure and further comprising disposing a separating element between the conductor loop and the press-forming device so as to separate the conductor loop from the press-forming device. 
   
   
     9. The method as recited in  claim 8 , wherein the conductor loop includes an outside and wherein the disposing of the separating element includes covering the outside of the conductor loop prior to performing the press-forming procedure. 
   
   
     10. The method as recited in  claim 9 , wherein the separating element is a separating film including a polyvinyl fluoride (PVF). 
   
   
     11. The method as recited in  claim 8 , wherein the separating element includes a separable coating provided on the press-forming device. 
   
   
     12. The method as recited in  claim 7 , wherein the individual wires have a heat-resistant insulation and further comprising impregnating the conductor loop before the fourth step with a binder including an easily penetrating, heat-curing resin. 
   
   
     13. The method as recited in  claim 12 , further comprising coating the individual wires over the insulation with a self-bonding lacquer that melts under the effect of heat. 
   
   
     14. The method as recited in  claim 12 , wherein the heat-curing resin contains an additive for increasing a thermal conductivity of the conductor bar. 
   
   
     15. The method as recited in  claim 1 , wherein the individual wires include round wires made of copper and having a conductor diameter ranging from 0.5 mm to 1.2 mm. 
   
   
     16. The method as recited in  claim 9 , further comprising performing a pre-press-forming procedure prior to disposing the separating element so as to give the conductor loop a cross sectional shape that approximates the final cross sectional shape. 
   
   
     17. The method as recited in  claim 1 , wherein the cabling of the individual wires and the winding of the stranded conductors are both carried out in the same rotational direction. 
   
   
     18. The method as recited in  claim 1 , wherein the cabling of the individual wires and the winding of the stranded conductors are carried out in opposite rotational directions. 
   
   
     19. The method as recited in  claim 1 , wherein the cabling is performed to form a plurality of identical stranded conductors each including a plurality of concentric layers of the individual wires having the same direction of rotation. 
   
   
     20. The method as recited in  claim 1 , wherein the individual wires are made of soft copper. 
   
   
     21. The method as recited in  claim 1 , further comprising wrapping at least every second one of the stranded conductors with a thin, stretchable filament or tape prior to the second step so as to protect the individual wires during the winding step. 
   
   
     22. The method as recited in  claim 1 , wherein the winding is performed so that the stranded conductors are wound in parallel onto the winding spindle and wherein the removing of the conductor loop includes pulling the conductor loop off of the winding spindle continuously or section-wise. 
   
   
     23. The method as recited in  claim 1 , wherein the press-forming procedure is performed so as to simultaneously gives the conductor loop the final cross sectional shape along the entire length of the conductor loop. 
   
   
     24. The method as recited in  claim 1 , further comprising helically winding each stranded conductor with an electrically insulating tape prior to the second step. 
   
   
     25. The method as recited in  claim 24 , wherein the insulating tape includes a stretchable fabric permeable to impregnating resin, and wherein the tape is stretched as it is wound onto the stranded conductor. 
   
   
     26. The method as recited in  claim 24 , wherein the insulating tape has a thickness ranging from 0.03 mm to 0.1 mm and includes a yarn or fabric including polyester fibers. 
   
   
     27. A method for producing a conductor bar of transposed stranded conductors for a large, rotating electric machine, the method comprising:
 in a first step, cabling a plurality of electrically insulated individual wires so as to form a plurality of identical stranded conductors each having an essentially circular cross section; 
 in a second step, helically winding the stranded conductors around a winding spindle according to a Roebel transposition so as to form a conductor loop, the winding spindle having a profile adapted to a final cross sectional shape of the conductor bar; 
 in a third step, removing the winding spindle from the conductor loop; and 
 in a fourth step, performing a press-forming procedure on the conductor loop so as to give the conductor loop the final cross sectional shape, wherein the fourth step includes, gluing together the individual wires during the press-forming procedure, wherein the gluing is performed by heating up the conductor loop in a press-forming device before and/or during the press-forming procedure and further comprising disposing a separating element between the conductor loop and the press-forming device so as to separate the conductor loop from the press-forming device. 
 
   
   
     28. The method as recited in  claim 27 , wherein the conductor loop includes an outside and wherein the disposing of the separating element includes covering the outside of the conductor loop prior to performing the press-forming procedure. 
   
   
     29. The method as recited in  claim 28 , wherein the separating element is a separating film including a polyvinyl fluoride (PVF). 
   
   
     30. The method as recited in  claim 27 , wherein the separating element includes a separable coating provided on the press-forming device. 
   
   
     31. A method for producing a conductor bar of transposed stranded conductors for a large, rotating electric machine, the method comprising:
 in a first step, cabling a plurality of electrically insulated individual wires so as to form a plurality of identical stranded conductors each having an essentially circular cross section; 
 in a second step, helically winding the stranded conductors around a winding spindle according to a Roebel transposition so as to form a conductor loop, the winding spindle having a profile adapted to a final cross sectional shape of the conductor bar; 
 in a third step, removing the winding spindle from the conductor loop; and 
 in a fourth step, performing a press-forming procedure on the conductor loop so as to give the conductor loop the final cross sectional shape, wherein the fourth step includes gluing together the individual wires during, the press-forming procedure, wherein the individual wires have a heat-resistant insulation and further comprising impregnating the conductor loop before the fourth step with a binder including an easily penetrating, heat-curing resin. 
 
   
   
     32. The method as recited in  claim 31 , further comprising coating the individual wires over the insulation with a self-bonding lacquer that melts under the effect of heat. 
   
   
     33. The method as recited in  claim 31 , wherein the heat-curing resin contains an additive for increasing a thermal conductivity of the conductor bar. 
   
   
     34. The method as recited in  claim 28 , further comprising performing a pre-press-forming procedure prior to disposing the separating element so as to give the conductor loop a cross sectional shape that approximates the final cross sectional shape. 
   
   
     35. A method for producing a conductor bar of transposed stranded conductors for a large, rotating electric machine, the method comprising:
 in a first step, cabling a plurality of electrically insulated individual wires so as to form a plurality of identical stranded conductors each having an essentially circular cross section; 
 in a second step, helically winding the stranded conductors around a winding spindle according to a Roebel transposition so as to form a conductor loop, the winding spindle having a profile adapted to a final cross sectional shape of the conductor bar; 
 in a third step, removing the winding spindle from the conductor loop; and 
 in a fourth step, performing a press-forming procedure on the conductor loop so as to give the conductor loop the final cross sectional shape, and further comprising wrapping at least every second one of the stranded conductors with a thin, stretchable filament or tape prior to the second step so as to protect the individual wires during the winding step. 
 
   
   
     36. A method for producing a conductor bar of transposed stranded conductors for a large, rotating electric machine, the method comprising:
 in a first step, cabling a plurality of electrically insulated individual wires so as to form a plurality of identical stranded conductors each having an essentially circular cross section; 
 in a second step, helically winding the stranded conductors around a winding spindle according to a Roebel transposition so as to form a conductor loop, the winding spindle having a profile adapted to a final cross sectional shape of the conductor bar; 
 in a third step, removing the winding spindle from the conductor loop; and 
 in a fourth step, performing a press-forming procedure on the conductor loop so as to give the conductor loop the final cross sectional shape, further comprising helically winding each stranded conductor with an electrically insulating tape prior to the second step. 
 
   
   
     37. The method as recited in  claim 36 , wherein the insulating tape includes a stretchable fabric permeable to impregnating resin, and wherein the tape is stretched as it is wound onto the stranded conductor. 
   
   
     38. The method as recited in  claim 36 , wherein the insulating tape has a thickness ranging from 0.03 mm to 0.1 mm and includes a yarn or fabric including polyester fibers.